A liquid-phase loop-mode argon purification system

Noble gas and liquid detectors rely on high chemical purity for successful operation. While gaseous purification has emerged as a reliable method of producing high -purity noble fluids, the requirement for large mass flows drives the development of liquid -phase purification. We constructed a medium -scale liquid argon (LAr) purification system based on a copper catalyst and 4 angstrom molecular sieve capable of purifying 1 t of commercial LAr 5.0 to a long effective triplet lifetime of tau(3) - 1.3 mu s. We further demonstrate that a quenched effective triplet lifetime of tau(3) - 1 mu s, due to contamination by air, can be recovered in loop -mode purification to tau(3) - 1.3 mu s after > 20 volume exchanges.